Fendt 1E.1.50 – Engine Control Unit (ECU) / A051: Y091 - Dispensing unit (fuel) not connected, short circuit to battery or short to ground

An electrical circuit fault indicating that the Y091 dispensing unit is not connected, has a short circuit to battery, or a short to ground. This prevents the engine control unit from properly regulating the fuel quantity fed to the high-pressure pumps, and the tractor will display a message indicating that the engine will stop after approximately 4 to 5 minutes.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• 200 Vario series (207, 208, 209, 210, 211)
• 300 Vario series (COM III)
• 400 Vario series (COM III)
• 700 and 800 Vario series (COM III, S4)
• 900 Vario series (COM III, S4, Gen6)

1. 1

   Check the wiring harness and connectors between the A051 Engine Control Unit and the Y091 dispensing unit for cable breaks, short circuits to the battery, or short circuits to ground

2. 2

   Measure the resistance of the Y091 dispensing unit coil (target value is approximately 3.6 ohms)

3. 3

   With the engine running but not under load, check the voltage level at the unit (should be approximately 4.3 VDC)

4. 4

   With the engine not under load, check the power consumption (should be approximately 1.2 ADC +/- 15%)

5. 5

   Read out the KWP/FC codes using the SERDIA or Fendias diagnostic tool to check for associated sub-codes (e.g., 00B0, 00B1, 00B2, 00B3, 00B6, 00B7, 00BA, or 00BC)

1. 1

   Turn off tractor

   Turn off the tractor and ensure the engine is stationary.

2. 2

   Locate dispensing unit

   Locate the Y091 fuel dispensing unit on the high-pressure fuel pump assembly.

3. 3

   Inspect electrical harness

   Disconnect the electrical harness to the dispensing unit and inspect the pins for corrosion, damage, or pushed-out terminals.

4. 4

   Perform multimeter checks

   Perform the multimeter diagnostic checks (resistance, voltage, and continuity to the ECU) on the wiring harness.

5. 5

   Repair wiring harness

   If a wiring fault is found, repair or replace the damaged section of the harness.

6. 6

   Replace dispensing unit

   If the wiring is intact but the dispensing unit fails the resistance/electrical tests, remove and replace the Y091 fuel dispensing unit. (Note: On some Deutz engines, it is highly recommended to replace the connecting harness/terminal contacts at the same time, as vibration wear on the connector is a common root cause of unit failure).

7. 7

   Reconnect harness

   Reconnect the wiring harness.

8. 8

   Clear fault codes

   Connect the SERDIA or Fendias diagnostic tool and clear the stored fault codes.

9. 9

   Verify repair

   Start the engine and verify that the rail pressure actual values match the target values (approx. 400 bar at idle, up to 1600 bar under full load) and that the 5-minute engine stop warning no longer appears.